Output Devices
**************

Output devices are configured elements in FFmpeg that can write multimedia data to an output device attached to your system.

When you configure your FFmpeg build, all the supported output devices are enabled by default. You can list all available ones using the configure option "--list-outdevs".

You can disable all the output devices using the configure option "--disable-outdevs", and selectively enable an output device using the option "--enable-outdev=OUTDEV", or you can disable a particular input device using the option "--disable-outdev=OUTDEV".

The option "-devices" of the ff* tools will display the list of enabled output devices.

A description of the currently available output devices follows.

alsa
====

ALSA (Advanced Linux Sound Architecture) output device.

Examples
--------

  * Play a file on default ALSA device:

          ffmpeg -i INPUT -f alsa default

  * Play a file on soundcard 1, audio device 7:

          ffmpeg -i INPUT -f alsa hw:1,7

AudioToolbox
============

AudioToolbox output device.

Allows native output to CoreAudio devices on OSX.

The output filename can be empty (or -) to refer to the default system output device or a number that refers to the device index as shown using: -list_devices true.

Alternatively, the audio input device can be chosen by index using the

-audio_device_index <INDEX>

, overriding any device name or index given in the input filename.

All available devices can be enumerated by using -list_devices true, listing all device names, UIDs and corresponding indices.

Options
-------

AudioToolbox supports the following options:

-audio_device_index <INDEX>
     Specify the audio device by its index. Overrides anything given in the output filename.

Examples
--------

  * Print the list of supported devices and output a sine wave to the default device:

          $ ffmpeg -f lavfi -i sine=r=44100 -f audiotoolbox -list_devices true -

  * Output a sine wave to the device with the index 2, overriding any output filename:

          $ ffmpeg -f lavfi -i sine=r=44100 -f audiotoolbox -audio_device_index 2 -

caca
====

CACA output device.

This output device allows one to show a video stream in CACA window. Only one CACA window is allowed per application, so you can have only one instance of this output device in an application.

To enable this output device you need to configure FFmpeg with --enable-libcaca. libcaca is a graphics library that outputs text instead of pixels.

For more information about libcaca, check: http://caca.zoy.org/wiki/libcaca

Options
-------

window_title
     Set the CACA window title, if not specified default to the filename specified for the output device.

window_size
     Set the CACA window size, can be a string of the form WIDTHxHEIGHT or a video size abbreviation. If not specified it defaults to the size of the input video.

driver
     Set display driver.

algorithm
     Set dithering algorithm. Dithering is necessary because the picture being rendered has usually far more colours than the available palette. The accepted values are listed with -list_dither algorithms.

antialias
     Set antialias method. Antialiasing smoothens the rendered image and avoids the commonly seen staircase effect. The accepted values are listed with -list_dither antialiases.

charset
     Set which characters are going to be used when rendering text. The accepted values are listed with -list_dither charsets.

color
     Set color to be used when rendering text. The accepted values are listed with -list_dither colors.

list_drivers
     If set to true, print a list of available drivers and exit.

list_dither
     List available dither options related to the argument. The argument must be one of algorithms, antialiases, charsets, colors.

Examples
--------

  * The following command shows the ffmpeg output is an CACA window, forcing its size to 80x25:

          ffmpeg -i INPUT -c:v rawvideo -pix_fmt rgb24 -window_size 80x25 -f caca -

  * Show the list of available drivers and exit:

          ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_drivers true -

  * Show the list of available dither colors and exit:

          ffmpeg -i INPUT -pix_fmt rgb24 -f caca -list_dither colors -

decklink
========

The decklink output device provides playback capabilities for Blackmagic DeckLink devices.

To enable this output device, you need the Blackmagic DeckLink SDK and you need to configure with the appropriate --extra-cflags and --extra-ldflags. On Windows, you need to run the IDL files through widl.

DeckLink is very picky about the formats it supports. Pixel format is always uyvy422, framerate, field order and video size must be determined for your device with -list_formats 1. Audio sample rate is always 48 kHz.

Options
-------

list_devices
     If set to true, print a list of devices and exit. Defaults to false. This option is deprecated, please use the -sinks option of ffmpeg to list the available output devices.

list_formats
     If set to true, print a list of supported formats and exit. Defaults to false.

preroll
     Amount of time to preroll video in seconds. Defaults to 0.5.

duplex_mode
     Sets the decklink device duplex/profile mode. Must be unset, half, full, one_sub_device_full, one_sub_device_half, two_sub_device_full, four_sub_device_half Defaults to unset.

     Note: DeckLink SDK 11.0 have replaced the duplex property by a profile property. For the DeckLink Duo 2 and DeckLink Quad 2, a profile is shared between any 2 sub-devices that utilize the same connectors. For the DeckLink 8K Pro, a profile is shared between all 4 sub-devices. So DeckLink 8K Pro support four profiles.

     Valid profile modes for DeckLink 8K Pro(with DeckLink SDK >= 11.0): one_sub_device_full, one_sub_device_half, two_sub_device_full, four_sub_device_half

     Valid profile modes for DeckLink Quad 2 and DeckLink Duo 2: half, full

timing_offset
     Sets the genlock timing pixel offset on the used output. Defaults to unset.

link
     Sets the SDI video link configuration on the used output. Must be unset, single link SDI, dual link SDI or quad link SDI. Defaults to unset.

sqd
     Enable Square Division Quad Split mode for Quad-link SDI output. Must be unset, true or false. Defaults to unset.

level_a
     Enable SMPTE Level A mode on the used output. Must be unset, true or false. Defaults to unset.

vanc_queue_size
     Sets maximum output buffer size in bytes for VANC data. If the buffering reaches this value, outgoing VANC data will be dropped. Defaults to 1048576.

Examples
--------

  * List output devices:

          ffmpeg -sinks decklink

  * List supported formats:

          ffmpeg -i test.avi -f decklink -list_formats 1 'DeckLink Mini Monitor'

  * Play video clip:

          ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 'DeckLink Mini Monitor'

  * Play video clip with non-standard framerate or video size:

          ffmpeg -i test.avi -f decklink -pix_fmt uyvy422 -s 720x486 -r 24000/1001 'DeckLink Mini Monitor'

fbdev
=====

Linux framebuffer output device.

The Linux framebuffer is a graphic hardware-independent abstraction layer to show graphics on a computer monitor, typically on the console. It is accessed through a file device node, usually /dev/fb0.

For more detailed information read the file Documentation/fb/framebuffer.txt included in the Linux source tree.

Options
-------

xoffset

yoffset
     Set x/y coordinate of top left corner. Default is 0.

Examples
--------

Play a file on framebuffer device /dev/fb0. Required pixel format depends on current framebuffer settings.

     ffmpeg -re -i INPUT -c:v rawvideo -pix_fmt bgra -f fbdev /dev/fb0

See also http://linux-fbdev.sourceforge.net/, and fbset(1).

opengl
======

OpenGL output device.

To enable this output device you need to configure FFmpeg with --enable-opengl.

This output device allows one to render to OpenGL context. Context may be provided by application or default SDL window is created.

When device renders to external context, application must implement handlers for following messages: AV_DEV_TO_APP_CREATE_WINDOW_BUFFER - create OpenGL context on current thread. AV_DEV_TO_APP_PREPARE_WINDOW_BUFFER - make OpenGL context current. AV_DEV_TO_APP_DISPLAY_WINDOW_BUFFER - swap buffers. AV_DEV_TO_APP_DESTROY_WINDOW_BUFFER - destroy OpenGL context. Application is also required to inform a device about current resolution by sending AV_APP_TO_DEV_WINDOW_SIZE message.

Options
-------

background
     Set background color. Black is a default.

no_window
     Disables default SDL window when set to non-zero value. Application must provide OpenGL context and both window_size_cb and window_swap_buffers_cb callbacks when set.

window_title
     Set the SDL window title, if not specified default to the filename specified for the output device. Ignored when no_window is set.

window_size
     Set preferred window size, can be a string of the form widthxheight or a video size abbreviation. If not specified it defaults to the size of the input video, downscaled according to the aspect ratio. Mostly usable when no_window is not set.

Examples
--------

Play a file on SDL window using OpenGL rendering:

     ffmpeg  -i INPUT -f opengl "window title"

oss
===

OSS (Open Sound System) output device.

pulse
=====

PulseAudio output device.

To enable this output device you need to configure FFmpeg with --enable-libpulse.

More information about PulseAudio can be found on http://www.pulseaudio.org

Options
-------

server
     Connect to a specific PulseAudio server, specified by an IP address. Default server is used when not provided.

name
     Specify the application name PulseAudio will use when showing active clients, by default it is the LIBAVFORMAT_IDENT string.

stream_name
     Specify the stream name PulseAudio will use when showing active streams, by default it is set to the specified output name.

device
     Specify the device to use. Default device is used when not provided. List of output devices can be obtained with command pactl list sinks.

buffer_size

buffer_duration
     Control the size and duration of the PulseAudio buffer. A small buffer gives more control, but requires more frequent updates.

     buffer_size specifies size in bytes while buffer_duration specifies duration in milliseconds.

     When both options are provided then the highest value is used (duration is recalculated to bytes using stream parameters). If they are set to 0 (which is default), the device will use the default PulseAudio duration value. By default PulseAudio set buffer duration to around 2 seconds.

prebuf
     Specify pre-buffering size in bytes. The server does not start with playback before at least prebuf bytes are available in the buffer. By default this option is initialized to the same value as buffer_size or buffer_duration (whichever is bigger).

minreq
     Specify minimum request size in bytes. The server does not request less than minreq bytes from the client, instead waits until the buffer is free enough to request more bytes at once. It is recommended to not set this option, which will initialize this to a value that is deemed sensible by the server.

Examples
--------

Play a file on default device on default server:

     ffmpeg  -i INPUT -f pulse "stream name"

sdl
===

SDL (Simple DirectMedia Layer) output device.

"sdl2" can be used as alias for "sdl".

This output device allows one to show a video stream in an SDL window. Only one SDL window is allowed per application, so you can have only one instance of this output device in an application.

To enable this output device you need libsdl installed on your system when configuring your build.

For more information about SDL, check: http://www.libsdl.org/

Options
-------

window_borderless
     Set SDL window border off. Default value is 0 (enable window border).

window_enable_quit
     Enable quit action (using window button or keyboard key) when non-zero value is provided. Default value is 1 (enable quit action).

window_fullscreen
     Set fullscreen mode when non-zero value is provided. Default value is zero.

window_size
     Set the SDL window size, can be a string of the form WIDTHxHEIGHT or a video size abbreviation. If not specified it defaults to the size of the input video, downscaled according to the aspect ratio.

window_title
     Set the SDL window title, if not specified default to the filename specified for the output device.

window_x

window_y
     Set the position of the window on the screen.

Interactive commands
--------------------

The window created by the device can be controlled through the following interactive commands.

q, ESC
     Quit the device immediately.

Examples
--------

The following command shows the ffmpeg output is an SDL window, forcing its size to the qcif format:

     ffmpeg -i INPUT -c:v rawvideo -pix_fmt yuv420p -window_size qcif -f sdl "SDL output"

sndio
=====

sndio audio output device.

v4l2
====

Video4Linux2 output device.

xv
==

XV (XVideo) output device.

This output device allows one to show a video stream in a X Window System window.

Options
-------

display_name
     Specify the hardware display name, which determines the display and communications domain to be used.

     The display name or DISPLAY environment variable can be a string in the format HOSTNAME[:NUMBER[.SCREEN_NUMBER]].

     HOSTNAME specifies the name of the host machine on which the display is physically attached. NUMBER specifies the number of the display server on that host machine. SCREEN_NUMBER specifies the screen to be used on that server.

     If unspecified, it defaults to the value of the DISPLAY environment variable.

     For example, dual-headed:0.1 would specify screen 1 of display 0 on the machine named ``dual-headed''.

     Check the X11 specification for more detailed information about the display name format.

window_id
     When set to non-zero value then device doesn't create new window, but uses existing one with provided WINDOW_ID. By default this options is set to zero and device creates its own window.

window_size
     Set the created window size, can be a string of the form WIDTHxHEIGHT or a video size abbreviation. If not specified it defaults to the size of the input video. Ignored when WINDOW_ID is set.

window_x

window_y
     Set the X and Y window offsets for the created window. They are both set to 0 by default. The values may be ignored by the window manager. Ignored when WINDOW_ID is set.

window_title
     Set the window title, if not specified default to the filename specified for the output device. Ignored when WINDOW_ID is set.

For more information about XVideo see http://www.x.org/.

Examples
--------

  * Decode, display and encode video input with ffmpeg at the same time:

          ffmpeg -i INPUT OUTPUT -f xv display

  * Decode and display the input video to multiple X11 windows:

          ffmpeg -i INPUT -f xv normal -vf negate -f xv negated